I have to disagree, I think on the ground Nog would be able to catch him in a triangle and standing, at his real ability, I don't know if he could KO Brock (no one has tested Brock's chin) but he would deffinitely edge out over Lessy. If Fedor couldn't knock out Nog, I really doubt Brock could.
I see where your coming from, but I have to disagree. Here's why.I'll argue even forgetting about Brock's rediculous spongeness.
Standing, Nog has slowed down considerably. It happens with age. So while he does have good boxing, he just doesn't have the speed anymore. Plus his chin is getting weaker just like Wanderlei's. So while he could probably hit Brock a lot, Nog has never really had much power in his punches. Take into account Brocks huge think skull, I don't think Nog can KO or even rock Brock. Brock however has giant power, a longer reach and more speed. He may not be as technically proficient, but he will connect eventually and really rock Nog. From there he will just make Nog stand up, and do it again and again until he gets the KO. And BTW, as a Fedor lover myself, Brock has way more power then Fedor.
On the ground, it's clear there is no way Brock will go to Nog's gaurd. Just like when he took Mir down and could have went into his gaurd, he made him standup. So it will start from half gaurd if on the ground. Nogeuira is very good at transitional positions and sweeps from there, but it's also very clear Brock will not allow any space at all to be created. His base is also rediculously solid and he's far stronger then Nog. So in all likelyhood, he will do the same thing to Nog as he just did to Mir. But if it were to be in Nog's gaurd, then it will be a little more even. However, Nog's gaurd defence depends a lot on wrist control. Brock's hands are just too big and powerful, so he can definitely negate Nog's defence. In term of offensively, while he may be able to get Brock in a triangle, I forsee a lot of powerbombs until Nog let's go.
Ofcourse, I'm talking about current Nog, as prime Nog was much faster and more durable, and likely could beat current Brock anywhere.